Devices for fastening electric cables



April 9, 1957 y .1. P. CAMZI 2,788,505

DEVICES FOR FASTENING ELECTRIC CABLES Filed May 26, 1 55 INVEN TOR.

JUL E5 PAUL n/wz/ BY United States Patent DEVICES FOR FASTENING ELECTRIC CABLES Jules P. Camzi, Geneva, Switzerland Application May 26, 1955, Serial No. 511,345

Claims priority, application Switzerland June 15, 1954 2 Claims. (Cl. 339-255) Devices for fastening electric cables to contact elements, such as pins and sockets, in which the cables are clamped by means of screws, have certain disadvantages because said screws tend to become slackened; the cables being then no longer held to the contact elements, the electric circuit is broken and the free end of one of the conductors may come into contact with an uninsulated part of another conductor and cause a short-circuit. In addition, the positioning of contact elements connected to the conductors in the spaces provided for them in the insulating casings is not easy, because said elements must take up a determined position in said spaces and are not held in that position by any retaining device when the casing is closed.

The clamping device forming the subject of the present invention obviates these disadvantages, by providing an efiective connection which cannot become undone accidentally, with the aid of simple and inexpensive elements.

The accompanying drawing illustrates by way of example one form of construction of the device of the invention.

Figures 1 to 4 are profile views of the elements constituting the clamping device;

Figure 5 shows an assembly, with sections, of said elements;

Figure 6 shows a general view of a plug, the pins of which are provided with the clamping device.

In this form of construction, the clamping device is constituted by the contact element 1 which in the case described is a pin, a cap 2, and a spring 3. The pin 1 has a collar 4 and a cone 5, which is surmounted by a cylindrical part 7 pierced by a hole 6. The cap 2 is hollowed conically, the hollow cone being followed by a hollow cylindrical part, as shown in broken lines in Figure 2, and has a shoulder 8 intended to engage in the spring 3. Figure 5 shows the assembly of the different elements of the device: the bated end 9 of the conductor cable is threaded into the hole 6, first passing through the spring 3 and the cap 2 and then being brought back into said cap 2. The insulating casing of the contact element has cavities in which the collar 4 and the cap 2 are housed, together with the spring 3, said collar and said spring bearing against the walls of the casing, whereby the spring is maintained under tension and applies the cap 2 against the wire and the latter against the cone, thus ensuring contact under constant pressure. Figure 6 illustrates the whole arrangement comprising an open two-pin plug, in which the insulating casing is of the usual type of plastic material, constituted by two symmetrical halves.

The contact element could contain an elbow bend.

In the case of a female plug, containing sockets instead of the pins, the device would be identical and be applied to the bottom part of the sockets.

With screw connection devices repeated pulling of the cables tends to slacken the screws and to break the contact between the cable and the contact element; the device of the present invention avoids this risk, since on the contrary traction on the cable tends to increase the pressure of the cap against the cable bearing against the cone and, consequently, to increase the clamping effect as the pull is increased. Moreover, the contact elements are very easily positioned in the cavities provided in the casings, the pressure of the spring 3 maintaining said elements in the position in which they have been placed, thus enabling the insulating casings to be easily closed. The spring 3 could be replaced by a flexible member of rubber, for example. The conical clamping walls could be replaced by inclined plane walls.

I claim:

1. In an electrical appliance having a contact element, a cable and means for clamping one end of the cable to the contact element, said means comprising a coneshaped projection on one end of the contact element, an aperture piercing said element transversely above said cone-shaped projection for receiving one end of the cable, whereby said cable end may engage one side of the coneshaped projection, pass through the aperture and thereafter engage the opposite side of the cone-shaped projection, a conically hollowed cap movably engaging the cable and the cone-shaped projection of the contact element, and a resilient member surrounding: the cable and having one end thereof engaging the cap for pressing the cap against the cone-shaped projection to tightly hold the cable between the conical surfaces of said cap and contact element.

2. A device as set forth in claim 1, wherein said contact element is provided with a collar and with a cylindrical portion between said collar and cone-shaped projection, the aperture for the cable being located in said cylindrical portion, and wherein the engagement of the resilient member with the cap is efiected by means of .a shoulder on said cap receiving one end of the resilient member.

References Cited in the file of this patent UNITED STATES PATENTS 2,714,197 Wharton July 26, 1955 FOREIGN PATENTS 25,906 France Mar. 6, 1923 971,100 France June 28, 1950 

